The invention relates to universal coupling mechanism for flexible torque-transmitting interconnection of rotatable input and output members, and in particular to such mechanisms which employ meshing gear teeth for torque transmission.
The conventional universal joint has remained essentially the same since its invention by Robert Hooke in 1676. It involves like input and output rotatable coupling members with bifurcated ends which are held in quadrature interlace by a first diametrically extending pin-axis connection of the bifurcated ends of the input member to an intermediate coupling member, and by a second diametrically extending pin-axis connection of the bifurcated ends of the output member to the same intermediate coupling member. Neat as Mr. Hooke's solution was, his coupling is necessarily severely limited as to tolerable degree of angular misalignment of the input and output rotary axes and as to the uniformity with which torque may be transmitted in the course of a single revolution of the coupling. Such limitations remain to this day, for such universal-joint constructions of which I am aware.